1. Field of the Invention
The present invention relates to a printing system for performing marginless printing on roll paper, and more specifically to a recording method and a recording device.
2. Description of the Related Art
In recent years, there has been an increasing need for printing photographs by a printer. Along with this need, the function of so-called “marginless printing” has become popular. In “marginless printing”, printing is performed on the entire surface of a paper sheet without leaving blank margins at sheet edges.
A structure for realizing marginless printing in the recording medium cut into a specified size in the conventional inkjet printer is shown in FIG. 2. In the conventional inkjet printer, an ink receiving slot 31 is arranged in a portion of a platen. Further, a paper sheet 32 is arranged so that edges of the paper sheet 32 (for example, horizontal edges, or vertical edges) are positioned over this ink receiving slot 31. When an ink drop 34 is jetted from a printing head 33, the ink drop 34 at the portion off the edge of the paper sheet (the portion without a paper sheet) is received by the ink receiving slot 31, and thereby marginless printing is carried out. However, this ink receiving slot 31 in the portion of the platen is not movable according to the width of a recording medium and is physically fixed. Accordingly, in the conventional inkjet printer, the width of the paper sheet on which marginless printing can be performed is restricted depending on the printer.
Next, it explains a structure for realizing marginless printing on a printing medium of roll paper. When marginless printing is carried out on a printing medium of roll paper, with regard to the horizontal edges of the paper sheet, printing is carried out as explained above. Meanwhile, with regard to the vertical edges, printing is carried out so that an image should be printed large enough to get out of the edges, and the portions out of the edges are cut off by a cutter for the roll paper (not shown), thereby the marginless printing is realized.
Thus, in both of the cut paper and the roll paper, in order to perform a completely marginless printing, an image is printed slightly beyond the paper size. Therefore, a printing image that is slightly larger than the paper size is required in the marginless printing.
As methods for realizing this printing, there are the following three methods.
Method 1
An image slightly larger than the paper size for printing is created by use of an application software, and the image is printed without being enlarged by a printer driver.
Method 2
A printer driver returns a resolution slightly larger than the resolution to be used for printing to an application software on a host computer, and by increasing the nominal number of pixels, a large printing image is obtained.
Method 3
As discussed in Japanese Patent Application Laid-Open No. 2002-091723 (corresponding to US Patent Appl. No. 2002-036665), by enlarging printing data from an application software to be larger than the paper size by a printer driver, a large printing image is created.
FIG. 3 illustrates the Method 3. In FIG. 3, the reference numeral 41 denotes a original size equivalent to an original image created by an application software, and reference numeral 42 denotes a marginless image size having a “protruding area” M necessary for enlarging the original size 41 and performing marginless printing. The reference numeral 43 denotes a print out size of a marginless printed matter obtained finally after printing the image and removing the vertical and horizontal protruding areas M.
However, when image data is enlarged according to the Method 1, it is necessary for a user to carry out a processing of enlarging the image to the necessary size on an application software, and this operation by the user becomes complicated.
Further, when image data is enlarged according to the Method 2 or the Method 3, an image at a specified edge is lost due to the influence of an aspect ratio, and an input image is impaired. This state is shown in FIG. 4A. In FIG. 4A, the reference numeral 61 denotes an image to be actually printed (input image), reference numeral 62 denotes an image enlarged to the size where marginless printing of the input image 61 is available while the aspect ratio thereof is maintained (image slightly larger than the printing paper size). Further, reference numeral 63 denotes a print out size obtained as the result of printing the enlarged image 62. Since the input image 61, the enlarged image 62, and the print out size 63 have all of a same aspect ratio, the difference between the long side and the short side of the input image 61 is large. If the aspect ratio becomes biased, the lack of the image in the longer direction is larger than the shorter direction.
With regards to the Method 3, for example, a method to obtain a printed matter with print out size 43 of A4 from an image with original size 41 of A4 is shown in detail. (Refer to FIGS. 3 and 5.)
First, at step S21, the size of the original size 41 is obtained. The size of the original size 41 is the same as the size of a paper sheet of A4 and is as shown below.SRC(x,y)=(210 mm,297 mm)
Next, at step S22, the minimum image size for marginless printing is calculated. If the protruding amount M from the vertical and horizontal edges of the paper sheet required for the marginless printing is 3 mm, the horizontal width and the vertical height of the paper sheets become 6 mm larger respectively. Therefore, the minimum image size for the marginless printing is as shown below.IMAGE(x,y)=SRC(x,y)+(2M,2M)=(216 mm,303 mm)
Next, at step S23, in order to obtain the image size for the marginless printing, magnification ratios of the image size for the marginless printing are calculated with respect to the original size in the vertical length and the horizontal width.Magnification ratio in x direction Rx=IMAGEx÷SRCx=216 mm÷210 mm=102.86%Magnification ratio in y direction Rx=IMAGEy÷SRCy=303 mm÷297 mm=102.02%
If the image for the marginless printing is generated by enlarging the image using the independent magnification ratios in x and y directions, the image is distorted. Therefore, the magnification ratios in the directions x and y are made identical. In this case, in order to eliminate the blank margins of the paper sheet, the larger magnification ratio (herein Rx) is adopted as the magnification ratio R (step S24).
Next, at step S25, the necessary image size is recalculated using the magnification ratio determined at the step S24.IMAGEx=210 mm×102.86%=216.0 mmIMAGEy=297 mm×102.86%=305.5 mm
When this image (216.0×305.5 mm) is printed onto the A4 size paper sheet (210×297 mm) (step S26), the image is lost by 6 mm in x direction, but by as much as 8.5 mm in y direction. This tendency becomes worse as the aspect ratio of the paper sheet becomes more biased.
According to the above method, when marginless printing of photograph data is performed, if the aspect ratio of the original photograph data is largely different from the aspect ratio of the paper sheet, edges of the original photograph data may be largely lost. Further, if loss in edges of the original photograph data is made small, margins (blank margins) are left in the print out image.